Jakarta, Indonesia Sentinel — Mount Semeru, located in Lumajang, East Java, has shown an increased volcanic activity since the start of 2025. Standing at 3,676 meters above sea level, the volcano has erupted 10 times since the early hours of Thursday, January 2, 2025.
According to Oke Zone, an official at the Semeru Volcano Observation Post states that the largest eruption on Thursday occurred at 8:51 AM local time. The ash column reached a height of 1,200 meters above the crater, or 4,876 meters above sea level. The ash plume was observed to be white to gray with moderate intensity, drifting northward.
Additionally, the Semeru Volcano Observation post reported seismic activity over the past 24 hours leading up to early Thursday. A total of 34 eruption quakes were recorded, with amplitudes ranging from 10 to 23 mm and durations lasting between 53 and 145 seconds. Additionally, one rockfall quake was detected, registering an amplitude of 3 mm and lasting 50 seconds.
New Year Eruptions
According to Antara, Mount Semeru reportedly erupts 10 times on the fist day after the new year on Wednesday, January 1, 2025, between 1:00 AM and 6:30 PM. Of these eruptions, only one eruptions at 5:20 AM was visually observed, with an ash column rising approximately 500 meters above the crater.
The ash plume was white to gray, with moderate intensity, drifting southwest. The other nine eruptions were obscured by thick fog, preventing visual confirmation.
Alert Status and Safety Measures
Mount Semeru remains at Level II (Alert) status, indicating ongoing volcanic activity. In response, the Bromo Tengger Semeru National Park (BB TNBTS) has taken precautionary measures, including suspending all hiking activities.
This decision aligns with directives from Forestry Minister Raja Juli Antoni. Originally planned from January 2 to January 16, 2024, the hiking trail closure has now been extended until January 19, 2024.
Activity Restrictions
The Center for Volcanology and Geological Hazard Mitigation (PVMBG) has issued warnings prohibiting all activities within 8 kilometers southeast of the Besuk Kobokan river basin, extending from the volcano’s summit.
Beyond this radius, residents are advised to avoid any activity within 500 meters of riverbanks along the Besuk Kobokan due to the potential for pyroclastic flows and lahar reaching up to 13 kilometers from the summit.
Read also : Mount Raung in East Java Erupts, Trapping 20 Hikers
Authorities have also urged the public to remain vigilant about potential pyroclastic flows, lava avalanches, and rain-triggered lahars along river valleys originating from Mount Semeru. Specific areas of concern include Besuk Kobokan, Besuk Bang, Besuk Kembar, and Besuk Sat rivers, along with smaller tributaries feeding into Besuk Kobokan.
Officials continue to monitor the situation closely and advise residents and tourists to follow safety protocols and updates from local authorities.
(Raidi/Agung)
